[PATCH] uml: initialize process FP registers properly

We weren't making sure that we initialized the FP registers of new processes
to sane values.

This patch also moves some defines in the affected area closer to where they
are used.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/include/registers.h

@@ -14,7 +14,7 @@ extern int restore_fp_registers(int pid, unsigned long *fp_regs);
 extern void save_registers(int pid, union uml_pt_regs *regs);
 extern void restore_registers(int pid, union uml_pt_regs *regs);
 extern void init_registers(int pid);
-extern void get_safe_registers(unsigned long * regs);
+extern void get_safe_registers(unsigned long * regs, unsigned long * fp_regs);
 extern void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer);
 
 #endif

arch/um/os-Linux/skas/mem.c

@@ -60,7 +60,7 @@ static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
 
 	multi_count++;
 
-	get_safe_registers(regs);
+	get_safe_registers(regs, NULL);
 	regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
 		((unsigned long) &batch_syscall_stub -
 		 (unsigned long) &__syscall_stub_start);

arch/um/os-Linux/skas/process.c

@@ -310,16 +310,12 @@ void userspace(union uml_pt_regs *regs)
 		}
 	}
 }
-#define INIT_JMP_NEW_THREAD 0
-#define INIT_JMP_REMOVE_SIGSTACK 1
-#define INIT_JMP_CALLBACK 2
-#define INIT_JMP_HALT 3
-#define INIT_JMP_REBOOT 4
 
 int copy_context_skas0(unsigned long new_stack, int pid)
 {
 	int err;
-	unsigned long regs[MAX_REG_NR];
+	unsigned long regs[HOST_FRAME_SIZE];
+	unsigned long fp_regs[HOST_FP_SIZE];
 	unsigned long current_stack = current_stub_stack();
 	struct stub_data *data = (struct stub_data *) current_stack;
 	struct stub_data *child_data = (struct stub_data *) new_stack;
@@ -334,7 +330,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 				      .timer    = ((struct itimerval)
 					            { { 0, 1000000 / hz() },
 						      { 0, 1000000 / hz() }})});
-	get_safe_registers(regs);
+	get_safe_registers(regs, fp_regs);
 
 	/* Set parent's instruction pointer to start of clone-stub */
 	regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
@@ -350,6 +346,11 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 		panic("copy_context_skas0 : PTRACE_SETREGS failed, "
 		      "pid = %d, errno = %d\n", pid, errno);
 
+	err = ptrace_setfpregs(pid, fp_regs);
+	if(err < 0)
+		panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
+		      "pid = %d, errno = %d\n", pid, errno);
+
 	/* set a well known return code for detection of child write failure */
 	child_data->err = 12345678;
 
@@ -457,6 +458,12 @@ void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
 	set_signals(flags);
 }
 
+#define INIT_JMP_NEW_THREAD 0
+#define INIT_JMP_REMOVE_SIGSTACK 1
+#define INIT_JMP_CALLBACK 2
+#define INIT_JMP_HALT 3
+#define INIT_JMP_REBOOT 4
+
 void thread_wait(void *sw, void *fb)
 {
 	sigjmp_buf buf, **switch_buf = sw, *fork_buf;

arch/um/os-Linux/sys-i386/registers.c

@@ -122,9 +122,12 @@ void init_registers(int pid)
 		      err);
 }
 
-void get_safe_registers(unsigned long *regs)
+void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
 {
 	memcpy(regs, exec_regs, HOST_FRAME_SIZE * sizeof(unsigned long));
+	if(fp_regs != NULL)
+		memcpy(fp_regs, exec_fp_regs,
+		       HOST_FP_SIZE * sizeof(unsigned long));
 }
 
 void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer)

arch/um/os-Linux/sys-x86_64/registers.c

@@ -70,9 +70,12 @@ void init_registers(int pid)
 		      err);
 }
 
-void get_safe_registers(unsigned long *regs)
+void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
 {
 	memcpy(regs, exec_regs, HOST_FRAME_SIZE * sizeof(unsigned long));
+	if(fp_regs != NULL)
+		memcpy(fp_regs, exec_fp_regs,
+		       HOST_FP_SIZE * sizeof(unsigned long));
 }
 
 void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer)

arch/um/sys-x86_64/ptrace_user.c

@@ -24,6 +24,13 @@ int ptrace_setregs(long pid, unsigned long *regs)
 	return(0);
 }
 
+int ptrace_setfpregs(long pid, unsigned long *regs)
+{
+	if (ptrace(PTRACE_SETFPREGS, pid, 0, regs) < 0)
+		return -errno;
+	return 0;
+}
+
 void ptrace_pokeuser(unsigned long addr, unsigned long data)
 {
 	panic("ptrace_pokeuser");

arch/um/sys-x86_64/user-offsets.c

@@ -57,7 +57,7 @@ void foo(void)
 #endif
 
 	DEFINE_LONGS(HOST_FRAME_SIZE, FRAME_SIZE);
-	DEFINE(HOST_FP_SIZE, 0);
+	DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
 	DEFINE(HOST_XFP_SIZE, 0);
 	DEFINE_LONGS(HOST_RBX, RBX);
 	DEFINE_LONGS(HOST_RCX, RCX);